Marine Geoid Undulation Assessment Over South China Sea Using Global Geopotential Models and Airborne Gravity Data

Abstract

ABSTRACT:Global geopotential models (GGMs) are vital in computing global geoid undulations heights. Based on the ellipsoidal height by Global Navigation Satellite System (GNSS) observations, the accurate orthometric height can be calculated by adding precise and accurate geoid undulations model information. However, GGMs also provide data from the satellite gravity missions such as GRACE, GOCE and CHAMP. Thus, this will assist to enhance the global geoid undulations data. A statistical assessment has been made between geoid undulations derived from 4 GGMs and the airborne gravity data provided by Department of Survey and Mapping Malaysia (DSMM). The goal of this study is the selection of the best possible GGM that best matches statistically with the geoid undulations of airborne gravity data under the Marine Geodetic Infrastructures in Malaysian Waters (MAGIC) Project over marine areas in Sabah. The correlation coefficients and the RMS value for the geoid undulations of GGM and airborne gravity data were computed. The correlation coefficients between EGM 2008 and airborne gravity data is 1 while RMS value is 0.1499.In this study, the RMS value of EGM 2008 is the lowest among the others. Regarding to the statistical analysis, it clearly represents that EGM 2008 is the best fit for marine geoid undulations throughout South China Sea.

Optimised gravity anomaly fields from along-track multi-mission satellite altimeter over Malaysian seas

“…However, there is a significant difference in RMSE value from the GO_ CONS_GCF_2_DIR_R5 model for tapering window width 200 with respect to their evaluation and verification with global marine gravity anomaly model that yielding RMSE value in the range of ± ± 18.5430 mGal to ± 19.2715 mGal. Hence, based on this results, it can also prove the statement from Yazid et al (2016), who mentioned that the combined GGMs solutions provide better fit to terrestrial gravity data than satellite-only models, is accurate. Besides, these combinations lead towards the best approximation of the Earth's gravitational field.…”